"It is estimated that seaweed floating down to the depths of the ocean naturally sequesters 173 million tons of carbon a year, about as much as New York City emits, and companies are looking for ingenious methods of harvesting this untapped energy. . . The new kelp farm concept is simple: the entire kelp farm gets moved down at night to receive nutrients from deeper waters, and up during the day to reach sunlight. . . Drone submarines would tow these kelp farms to new waters, communicating with harvesters by satellite, which would save labour costs. The drones could also submerge the farms to avoid big storms and passing ships."